Growing on till in Rhode IslandBotanical illustration
Pityopsis falcata, commonly known as sickleleaf silkgrass,sickle-leaved golden aster, and New England Golden aster[4], is perennial plant in the family Asteraceae native to the northeastern Atlantic Coastal Plain of the United States.
P. falcata is an herbaceous perennial that reaches 10-40 cm in height. It is characteristically caespitose, arising from a dense mass of fibrous roots and rhizomes.[5] The erect stems are sometimes branched, occasionally reddish-brown in color, striated, and covered in long silky hairs.[6]
The basal leaves usually wither by the time the plant flowers, and are shorter than the cauline leaves. The sessile cauline leaves are covered in trichomes, falcate in shape (giving the species its epithet falcata), and often folded along the midvein.[6]
The flowerheads, usually 4-10 but upwards up 25 per plant, are arranged in corymbiform arrays. The peduncles are 1-4 cm long, have sparse bracts, and are covered in fine white woolly hair. The involucres are bell-shaped, 5-8 mm. The phyllaries are in series of 5-6, with tufts of hairs at the top. There are 9-15 yellow ray florets and 30-60 disc florets. P. falcata blooms throughout the summer and fall.[6]
P. falcata has a chromosome count of (or ).[7] The most recent phylogenetic analyses indicate that it is most closely related to P. ruthii, with the two being considered sister species.[8]
In 1949, a specimen of P. falcata was collected along Canadian National Railway tracks west of Toronto.[9] This is the only reported occurrence of the species in Canada and was apparently a vagrant individual.[5]
In 1955, a specimen reported as P. falcata was collected along a beach in St. Petersburg, Florida. It is likely that this was a misidentified individual of P. tracyi, which is common in the state.[4][5]
Ecology
Where they co-occur, Schinia tuberculum, the golden aster flower moth, is a major pollinator of P. falcata. Elsewhere in its range, this moth relies on other species of Pityopsis, such as P. graminifolia, as a food source.[10]
Specific threats to the species are not well documented, though like other coastal endemics, P. falcata is potentially threatened by development, increased pressure from human recreation, sea level rise, coastal erosion, and invasive species. The overall impact of these threats, however, may be negligible due to the species' high local abundance and apparent tolerance of moderate disturbance, having been observed colonizing cleared habitats near roads and utility corridors.[13][11]
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